Hi,
I had Jerome Clingan at Clingan Guitars in Collingwood install a preamp for my recently.
It was a pretty involved job installing a 4 band Mike Pope pre into an originally passive Roscoe Beck and needed some routing. Jerome did a great job, was reasonably priced and I highly recommend him. Tell him Ruben recommended him to you. I think it's worth paying $100 - $200 just to have the piece of mind knowing that it's done properly. No cracked soldering or buzzing earth issues. Just pay for it once and have it done properly I reckon.
Cheers